1. Field of the Invention
The present invention is in the field of cathode ray tubes, and more specifically, relates to an improved fluorescent screen formed on the inner surface of the face plate.
2. Description of the Prior Art
Several types of projectors have been suggested for enlarging and projecting an image of a cathode ray tube on a screen. The most common type of projector uses a so-called projection type display. The cathode ray tube for the projector is usually energized at a level of approximately 15 to 20 times that of ordinary color cathode ray tubes, thereby causing the fluorescent material of the screen to emit higher intensity light. With a small size projector tube, however, the power required may be so high that the fluorescent material layer is likely to separate from the face plate by the action of the electron beam energy applied.
In a typical cathode ray tube structure of the prior art, the outer surface of the tube constitutes a face plate and a fluorescent material layer is formed on the inner surface of the face plate. A metal backing layer is usually provided behind the fluorescent screen, and is formed by vacuum deposition. An intermediate layer such as an acrylic resin is usually interposed between the back of the fluorescent screen and the front of the metal backing layer. This type of fluorescent screen, as previously mentioned, has disadvantages when used as a projector of the type mentioned.